FIG. 1 illustrates a known method for implementing bi-directional servo motor control to the motor 22. Motor 22 direction and power are controlled by solid state switching transistors 14, 16, 18 and 20 connected in a conventional H-bridge as shown receiving power from the +V line 11 and ground 15. The transistors 14, 16, 18 and 20 are controlled by bridge logic 12, receiving commands on bus 10 from a controller. Motor position is sensed by a position sensor 24 and position feedback to the controller is provided on line 26.
The motor configuration shown requires the four solid state switching transistors 14, 16, 18 and 20 shown, which, for high powered motors, can be costly. Known methods for bi-directional motor control are also available using only two switching solid state transistors. However, such methods require both +V and -V power supply lines or provide to the motor only half of the voltage difference between the +V and ground supply lines.